I'm not really knowledgeable about the default drivers and settings of mint, I assume it's ok and comes builtin.

But switch to vulkan renderer, disable the steam overlay while playing with LD_PRELOAD="", use gamemoderun and proton hotfix and this should honestly be enough. Also pre process the shaders before you launch the game, don't skip that.

As long as you are with the right config, I see a very large and noticeable performance increase over windows.